Bone Harvesting

ABSTRACT

Methods and devices for harvesting cancellous bone are disclosed. The bone-harvesting device may include a cannula and a bone receptacle in communication with the cannula, wherein the cannula including a cutting surface positioned at or adjacent the distal end, the cutting surface being oriented at an angle, the angle being greater than 90 degrees relative to the longitudinal axis of the cannula, and the harvested bone is adapted to move from a position adjacent to the cutting surface through the cannula into the bone receptacle. The cutting surface of the cannula may be positioned at or adjacent the distal end, and positioned at least in part radially outward of the outer face of the cannula. The cannula may include a cutting surface positioned at or adjacent the distal end and an occluding geometry that partially occludes the distal end of the cannula adjacent the cutting surface. In addition, a suction port may be provided in communication with the bone receptacle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application that claims prioritybenefit to a U.S. patent application entitled “Bone Harvesting,” whichwas filed Nov. 6, 2017 and assigned Ser. No. 15/804,293, which was acontinuation application that claimed priority benefit to a U.S. patentapplication entitled “Bone Harvesting,” which was filed Oct. 24, 2014and assigned Ser. No. 14/523,252 (now U.S. Pat. No. 9,833,248, issuedDec. 5, 2017), which was a continuation application claiming prioritybenefit to a PCT application entitled “Bone Harvesting,” which was filedon Mar. 15, 2013 and assigned Serial No. PCT/US2013/032531, and which inturn claimed priority benefit to U.S. provisional patent applicationsdesignated by Ser. No. 61/640,313, filed Apr. 30, 2012, and 61/643,662,filed May 7, 2012, all of which are hereby incorporated by referenceherein in their entirety.

SUMMARY

Methods and devices for harvesting cancellous bone are disclosed.

BACKGROUND

Bone grafts are used in surgical procedures that require the fusion,healing or joining of bones. Often bone grafts are harvested from thecancellous bone of a patient's own body, for example from the iliaccrest, the fibula, the ribs, the mandible, or any other area wherecancellous bone is accessible.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows a partial cross-section of a bone-harvestingdevice.

FIG. 2 schematically shows part of a bone-harvesting device harvestingcancellous bone.

FIG. 3 schematically shows the curved distal portion of abone-harvesting device.

FIGS. 4-6 schematically show three bone-harvesting devices withdifferent curved distal portions.

FIG. 7 schematically shows a perspective view of the exterior of abone-harvesting device of FIG. 1.

FIG. 8 schematically shows the cap shown in FIG. 1.

FIG. 8A schematically shows the cap shown in FIG. 1 in use.

FIGS. 8B-8E schematically show a separate volume-adjustable plunger.

FIGS. 9A and 9B schematically show the underside of the cap shown inFIG. 8.

FIG. 10 schematically shows an embodiment of the distal end of a cannulain a bone-harvesting device.

FIG. 11 schematically shows a cross section of an embodiment of thedistal end of a cannula in a bone-harvesting device.

FIG. 12 schematically shows the distal portion of a cannula with nooccluding member.

FIG. 13 shows the distal portion of a cannula with an occluding memberattached.

FIG. 14 schematically shows another embodiment of a distal tip of acannula.

FIGS. 15, 16 and 17A-C schematically show different cavities excavatedby different bone harvesting devices.

FIGS. 18A-C illustrate a benefit of having a bone harvesting device witha partially occluded tip

FIGS. 19A and B schematically show a bone harvesting device with ahandle flattened on one side.

FIGS. 20A and B schematically show a bone harvesting device with aflexible or swivel suction port.

FIGS. 21A-C schematically show a bone harvesting device with varioustypes of suction port locations and orientations.

FIGS. 22A and B schematically show a bone harvesting device withmultiple suction ports.

FIG. 23 schematically shows a bone harvesting device with a blood orbiological material reservoir in the suction line.

FIG. 24 schematically shows a bone harvesting device with depth markingsalong the tapered or non-tapered cannula.

FIG. 25 schematically shows a bone receptacle and screw-on cap withalignment markers.

FIG. 26 shows a bone harvesting device with interchangeable distalportions.

FIG. 27 schematically shows a bone harvesting device with a cannulahaving various different cross-sectional geometries.

FIG. 28 schematically shows a bone harvesting device with a cannulahaving a wall thickness that varies along its length.

FIG. 29 schematically shows a cap for a bone receptacle with varioussealing points.

FIG. 30 schematically shows a bone harvesting device in which thecannula portion may be curved.

FIG. 31 schematically shows a bone harvesting devices including twocannulas in various orientations.

FIGS. 32A-C schematically show an actuated distal tip.

FIGS. 33A-C schematically show different sharpened distal tips.

DETAILED DESCRIPTION

FIG. 1 schematically shows a partial cross-section of a bone-harvestingdevice 1 for harvesting cancellous bone. The bone-harvesting deviceincludes a bone receptacle 2 and a cannula 3. The cannula has a straightproximal portion 4 and a curved distal portion 5. The bone receptacle 2has an entry port 6 connected to the cannula 3. The bone receptacle alsohas a suction port 7 where a suction hose can be attached so as to drawthrough the distal end of the cannula, through the cannula 3 and intothe bone receptacle 2. In this case, the suction port 7 is formed on acap 8 that forms an airtight seal with the bone receptacle 2 by way ofan o-ring 9. Other sealing arrangements are also possible such as aninterference fit, and/or built in grooves or seal designs. Inside thebone receptacle, the suction port is covered by a filter 10, designed toallow passage of blood, air and other fluid and biological materials,but not particles of bone above a certain size. The filter may pass onlythose bone particles whose minimum dimension is below a certain length,for example 0.5 millimeters, trapping other particles in the bonereceptacle. The cap 8 may also have a plunger 11 for removing harvestedbone (shown in more detail in FIGS. 8 and 8A). The exterior of the bonereceptacle is textured 12 for use as a handle, although this is anoptional feature. A wide variety of materials may be used for thevarious pieces. For example the cap 8 and bone receptacle 2 may beplastic, and the cannula 3 may be metal. In some embodiments, the devicemay be disposable, intended for single-use, while in other embodimentsthe device is reusable. The bone receptacle may be transparent so thatthe operator can see the harvested bone. A transparent bone receptaclemay be marked with volume measurements (for example in cubiccentimeters) allowing the user to measure how much bone has beenharvested. Similarly, the cannula 3 can include length markings to allowthe user to know how deeply the cannula 3 has been advanced as shown inFIG. 24.

FIG. 2 schematically shows part of a bone-harvesting device harvestingcancellous bone. In order to harvest cancellous bone, the cortical bone13 is opened, for example with a drill or reamer, to reveal theunderlying cancellous bone 14. In opening the cortical bone, the surgeonmay also create a cavity in the cancellous bone. This access hole onlyneeds to expose the cancellous bone in the boney region before thebone-harvesting device can be used. The cannula 3 is then advanced intothe cavity.

The bone harvesting device has a hollow cannula with a straight proximalportion 4 and a curved distal portion 5. In some embodiments thecross-sectional geometry of the proximal portion 4 changes along itslength, for example it may be tapered; as shown the cross-sectiongeometry of the proximal portion 4 is constant along its length. (SeeFIGS. 19A and B.) Part of or all of the distal tip of the cannula issharpened to form a cutting edge 15. This cutting edge can be all or aportion of the circumference of the distal portion 5. This tip can besharpened from the outer wall, inner wall or both directions as shown inFIGS. 33A-C. The distal end of the hollow cannula may be partiallyoccluded by an occluding member 16. The user would initiate a pilot holeusing standard tooling such as a reamer or trephine to create a smallaccess hole to expose the cancellous region of the boney region. Oncethe cancellous region is exposed, the bone harvesting device is ready tobe inserted. The user advances the distal cutting tip into the accesshole and initiates small rotational strokes to advance the device deeperinto the boney space while enlarging the cavity. As the cavity enlargesthe user can advance the bone harvesting device into the bone cavity,moving it laterally so that the cutting edge 15 contacts the cancellousbone wall of the cavity, and pulling the bone-harvesting device upward,so that the cutting edge 15 scrapes a portion of cancellous bone 17 intothe bone-harvesting device to be harvested. The bone-harvesting devicefeatures and enables the user to implement rocking, scraping, curetting,carving and rotational cutting strokes. The harvested portion ofcancellous bone 17 is pulled up through the cannula by the applicationof suction at the proximal end of the cannula (not shown in FIG. 2). Theharvested portion of cancellous bone 17 will necessarily fit through thecannula because the occluding member 16 limits the size of the boneportion that enters the distal portion 5. This helps to prevent clogs.The cannula 3 may have constant cross-sectional size and shape, or itmay taper along its length. For example, the cannula may have circularcross-sectional shape with the proximal portion larger than the distalportion. The proximal portion may be a steep conical frustum. Taperingthe cannula to larger cross-sectional area more proximally may also helpto prevent clogs. The combination of tapering and the occluding platemember helps avoid clogging of the device.

FIG. 3 schematically shows the curvature of the curved distal portion 5.The straight proximal portion 4 defines an axis 18. The distal portion 5curves through an arc whose angular extent is labeled a. As shown inFIG. 3, α is about 135 degrees. Other embodiments may include distalportions that curve through an arc whose angular extent is in the rangeof 90 to 180 degrees, 100 to 170 degrees, 110 to 160 degrees, 120 to 150degrees, or 130 to 140 degrees. Alternative embodiments may include adistal portion that curves through an arc whose angular extent is lessthan 90 degrees (as shown in FIG. 14, for example). Existingbone-harvesting devices typically do not curve through any arc at all,i.e., they have an angle α of zero degrees, so that the cutting edge issimply the lower end of a straight cannula. Enabling the plane ofcutting to extend past 90 degrees enables the aforementioned cuttingstrokes as well as the capability to achieve a cavity profile as shownin FIGS. 16 and 17.

FIGS. 4-6 schematically show three bone-harvesting devices withdifferent curved distal portions. FIG. 4 schematically shows a distalportion 19 that curves through an arc of 180 degrees. In this 180-degreeembodiment, the sharpened cutting edge 20 is shown facing directlyupward. When applied to a vertical cavity wall and pulled upward by theuser, the vertical cutting edge 20 cannot apply any horizontal force tothe wall of the cavity; there is no horizontal component to the actionof the cutting edge 20. FIG. 5 schematically shows a distal portion 21that curves through an arc of about 135 degrees. When applied to avertical cavity wall and pulled upward by the user, the cutting edge 22includes components that are both vertical and horizontal, so that thecutting edge 22 can cut both into the wall and also upward along thesurface of the wall. FIG. 6 schematically shows a distal portion 23 thatcurves through an arc of just 90 degrees. When applied to a verticalcavity wall and pulled upward by the user, the horizontal cutting edge24 is directed perpendicular to the motion and therefore will not cutinto the cavity wall at all, instead just sliding along the surface. Adistal portion that curves through an arc of more than 90 degrees butless than 180 degrees will be preferred for some applications. With sucha curve, when the user forces the distal end of the bone-harvestingdevice against the cavity wall and drags the bone-harvesting deviceupward, the cutting edge will contact with the cavity wall with both ahorizontal component, allowing the cutting edge some purchase on thecancellous bone, and also a vertical component, allowing the cuttingedge to peel cancellous bone off the cavity wall.

FIG. 7 schematically shows a perspective view of the exterior of thesame bone-harvesting device 1 as FIG. 1, showing the bone receptacle 2,the cannula 3, the straight proximal portion of the cannula 4, thecurved distal portion of the cannula 5, the suction port 7, the cap 8,the textured handle 12, the cutting edge 15, and the occluding member16.

FIG. 8 schematically shows in more detail and in two perspectives, thecap 8 of FIG. 1. The suction port 7 is visible on the exterior of thecap 8. The interior of the cap 8 can include a plunger 25. Harvestedcancellous bone is pulled through the cannula under suction and passesfrom the cannula into the bone receptacle through the plunger plate 26by way of an opening 27. To remove harvested bone from the bonereceptacle, the user can unscrew the cap 8 and lift the bone out of thereceptacle contained by the plunger 25 and the plunger plate 26.Alternatively, the cap may be secured to the receptacle by any otheruseful method such as a latch, an interference fit, clips, etc.

FIG. 8A schematically shows the cap shown in FIG. 1 in use. Once thecancellous bone 17 has been harvested, the cap 8 can be unscrewed fromthe bone receptacle and handle 12. As the cap 8 and its plunger 25 andplunger plate 26 are lifted out of the bone receptacle (in the directionmarked by the arrow), the cancellous bone 17 is lifted out along withthe cap 8 contained by the plunger 25 and plunger plate 26. Inembodiments lacking a plunger, the cap is unscrewed and an elongatedtool such as an osteotome can be utilized to scoop out the bone from thebone receptacle.

FIGS. 8B-8E schematically show a separate volume-adjustable plunger. Astop disc 801 can be snapped into a variety of slots on plunger 802 todefine a desired volume. The disc can be alternatively thread, groovefit, male to female connect, or interference fit into place. With thedisc 801 installed, the plunger 803 defines a chosen volume to be filledwith harvested bone. FIG. 8C shows the plunger 803 empty and filled withharvested bone. FIG. 8D shows a closeup of the assembled plunger fromoutside the bone harvester, and, schematically, the plunger filled withharvested bone. FIG. 8E shows an exploded device including thevolume-adjustable plunger and stop disc. The bone-harvesting devicewithout said plungers and only a cap, or any of the preceding plungerscan also be used with a bone packing accessory to push the bone to thebottom of the bone receptacle thereby facilitating bone volumemeasurement.

FIG. 9A schematically shows the underside of a cap 8 with a filter 28.As shown, the filter is a separate piece that snaps on to posts 29, 30,31, but the filter may also be integral with the cap 8. In this case thefilter includes sieves 32, 33, 34 (a fourth is not visible on the backside of the filter), but may include any number. This filter fullycovers the entrance to the suction port inside the cap 8, so that fluid(for example blood, or air) passing to the suction port 7 must travelthrough the sieves 32, 33, 34. The sieves 32, 33, 34 are fine enough tocapture and prevent passage of bone particles above a certain size. Forexample, the sieves 32, 33, 34 may be sized so that all bone particleswhose smallest dimension is greater than 0.5 millimeters are caught bythe sieves 32, 33, 34 and remain in the bone receptacle even when thereceptacle is under suction. Alternatively, the bone receptacle may bedesigned for operation without any filter by tuning the suction flowrate and the interior geometry of the bone receptacle to trap boneparticles of a particular size range.

FIG. 9B schematically shows the underside of such a cap 8 with trappedbone pieces. The multiple sieves allow for one sieve 32 to be cloggedwith bone pieces while the other or others 33, 34 remain free tomaintain suction. In a cap with only a single sieve 37, a single clogcan block suction. By including sieves having different orientations,some sieves can remain clear while others may be blocked by largeparticles. As shown, the filter includes at least two sieves (in thiscase four) no two of which are parallel. The filter could includenon-planar sieves, such as sieves having an undulating or sinusoidalform, or a single sieve structured so that parts of it can remain clearwhile other parts may be blocked. For example, a filter consisting of asingle sieve could have a sieve in the form of a geometric prism, or ahemisphere or the like.

FIG. 10 schematically shows an embodiment of the cannula 4. In use, thecannula will typically have a sharpened cutting edge. Duringmanufacturing, the cannula 4 may be formed with a relatively blunt edge35 that can be later sharpened. It can be sharpened from variousdirections as shown in FIGS. 33A-C. The occluding member 16 can eitherbe integral with the rest of the cannula, as shown in FIG. 10, or can bea separate piece that is affixed to distal portion of the cannula 4. Thesharpness of the cutting edge may be calibrated to make it easy for auser to cut through cancellous bone, but difficult or impossible to cutthrough cortical bone. This is a safety feature that will help a user toonly harvest the desired cancellous bone, and keep the opening in thecortical bone as small as possible so as to keep the procedure minimallyinvasive. The cutting edge is tuned to provide tactile feedback for theuser to be able to discern between cortical and cancellous bone.

FIG. 11 schematically shows an embodiment of the distal portion 5 of thecannula 4. In this embodiment, the occluding member 36 is not planar, asshown in other embodiments, but instead is curved. In some contexts, thecurvature may help to prevent bone from getting stuck on the occludingmember 36.

FIG. 12 schematically shows the distal portion 5 of the cannula with nooccluding member. The cutting edge 15 is shown sharpened. FIG. 13 showsthe same distal portion 5 of the cannula with an occluding member 16attached and partially occluding the distal end of the cannula. Whilethe occluding member 16 can help to prevent clogs by limiting the sizeof harvested bone pieces entering the cannula, it is not necessary tothe functioning of the bone-harvesting device. The bone-harvestingdevice as shown in FIG. 12, with no occluding member, may be preferredin certain situations.

FIG. 14 schematically shows a cannula 40 with a straight proximalportion 41 and a curved distal portion 42. The curved distal portion 42has a cutting edge 43 at its tip, and an occluding member 44. Unlike theembodiment shown in FIG. 1, the embodiment of FIG. 14 includes a distalportion 42 that curves through an arc whose angular extent is less than90 degrees but more than 0 degrees. This curved distal portion allowsthe user to harvest cancellous bone 45 using a downward motion,advancing the distal tip into the cancellous bone, rather thanharvesting the bone by dragging the tip upward toward the user. Theoccluding member may be an optional feature to this embodiment; however,the inclusion of this feature is expected to improve the performance.

In some embodiments, the cancellous bone is cut only with the cuttingedge of the distal tip. But other embodiments may include additionalcutting technologies, for example, ultrasonic vibration, supersonicvibration, piezoelectric microvibration, or abrasive water jet cutting.

The device can also include technology to allow the user to sense howthe distal tip is interacting with the bone, even when the tip cannot bedirectly visualized, for example, by use of an infrared or visible lightcamera, possibly an endoscopic camera, ultrasound visualization,piezoelectric sensors, or pressure or force sensors. Any such sensorscan provide feedback to the user.

The device can also include indicia that may allow the user to know theorientation of the cutting edge and the curved distal portion, even whenthe distal portion cannot be directly visualized. The indicia may bestructural, or drawn, etched, painted, etc., onto a handle portion, sothat the user may perceive, for example by sight or feel, theorientation of the hidden distal tip of the device as shown in FIGS. 19Aand B.

The cutting edge can have varying geometry such that, when the tip ismoved in one direction a certain type of cutting motion is executed,while a different cutting motion is executed on a stroke in a differentdirection.

The cannula can include a low-friction coating on its interior toimprove passage of harvested bone through the cannula into the bonereceptacle. Possible coatings include Teflon® PTFE, Teflon® TFE, Teflon®S, Teflon® FEP, Teflon® PFA, Eclipse®, Dykor®, Xylan®, Xylan® XLR,Xylar®, Xylac®, various ceramics, the TEC-thermcote family of materials,and the TEC-fluorcote family of materials.

In some embodiments, a bone-harvesting device can include a cannula anda bone receptacle. The cannula can include a proximal end, a straightproximal portion, adjacent to the proximal end, that defines an axis, acurved distal portion that bends through an angle of at least 90 degreesand no more than 180 degrees relative to the axis, a distal end,adjacent to the distal portion, at least a part of the distal end beingsharpened to form a cutting edge, and an occluding member thatpartially, but not fully, occludes the distal end. The bone receptaclecan include a suction port and an entry port. The entry port can beattached to the proximal end of the cannula such that, when suction isapplied to the suction port, the suction draws from the distal end ofthe cannula, through the cannula, and into the bone receptacle. In otherembodiments, the curved distal portion can bend through an angle of morethan 0 degrees but less than 90 degrees.

In some embodiments the cannula can include a proximal end, a straightproximal portion, a curved distal portion, a distal end adjacent to thedistal portion, at least a part of the distal end being sharpened toform a cutting edge, and an occluding member that partially, but notfully, occludes the distal end. The bone receptacle can include asuction port, an entry port, and a filter that (a) fully covers thesuction port, (b) is permeable to fluid, and (c) is impermeable toparticles of cancellous bone whose smallest dimension is more than 0.25millimeters in size (for example). The entry port can be attached to theproximal end of the hollow cannula such that, when suction is applied tothe suction port, the suction draws from the distal end of the cannula,through the cannula, and into the bone receptacle.

FIGS. 15 and 16 schematically show one difference between prior art boneharvesters and the device shown in FIG. 2. FIG. 15 shows a boneharvester with no curve in the distal portion. The straight distalportion 1501 can pivot in the pilot hole 1502. But no matter how it isturned about its axis, the straight distal portion 1501 cannot harvestbone the is not directly visible along a straight line of sight throughthe pilot hole within the range of angles through which is it possibleto pivot the straight distal portion 1501. The resulting cavity 1503 isgenerally conical. As shown in FIG. 16, a curved distal end 1601 likethe one shown in FIG. 2, can harvest a much larger volume of bone.Similar to the straight distal end 1501, the curved distal end 1601 canpivot in the pilot hole 1602. But because of the curve, the curveddistal end can be advantageously turned about its axis to excavateotherwise unreachable cancellous bone. The resulting cavity 1603 can belarger and can include regions not visible along any line of sightthrough the pilot hole 1602.

FIGS. 17A-C illustrate the same idea. FIG. 17A shows a generally conicalregion of excavated cancellous bone beneath a layer of compact bone, acavity that could possibly be made with a bone harvesting device havinga straight distal portion. FIG. 17B shows a larger, generallybell-shaped region of excavated cancellous bone beneath a layer ofcompact bone, a cavity that could be made with a bone harvesting devicehaving a curved distal portion. FIG. 17C shows the difference betweenthe two cavities, illustrating the additional cancellous bone availableto the device with the curved distal portion.

FIGS. 18A-C illustrate a benefit of having a bone harvesting device 1801with a partially occluded tip 1802. When a first portion of bone 1803 iscarved and pushed into the distal end 1801 with a first cutting stroke1804, the first portion will typically fill the distal opening, and willoften be stuck in the distal opening by slight interference with thedistal portion. On the second stroke 1805, a second portion of bone 1806will be pushed into the distal end, and will displace the first portionof bone 1803, pushing the first portion farther into the harvestingdevice. Once the second stroke is complete and the first portion isfreed, the first portion will experience a suddenly strengthened forcedue to the applied negative pressure in the cannula so that the firstportion will be pulled up the cannula into the handle (not shown). Thiseffect will be present whenever a subsequent portion of bone frees aprevious portion of bone, but it will be exaggerated when the cannula istapered so as to broaden toward the proximal end and the handle. Thiswith the added concentration of pressure due to the occluding memberprovides a continuous collection method. One benefit of such a system isthat bone can be harvested continuously without withdrawing the devicefrom the cavity.

FIGS. 19A and B schematically show a bone harvesting device with ahandle flattened on one side. The generally cylindrical or conicalhandle 1901 can be flattened 1902 on one side. The flattened side 1902can be aligned 1903 with the curvature of the cutting tip so that a userwho is unable to directly visualize the tip can nonetheless always beaware of its orientation. The flattened side 1902 can be clear to allowthe user to see the harvested bone being collected in the handle 1901.The flattened side 1902 can also include graduations 1904 to allow auser to estimate the quantity of bone harvested. The orientation of thecurvature of the cutting could alternatively be noted by colors,shading, raised or grooved or bossed or embossed tactile features.

FIGS. 20A and B schematically show a bone harvesting device 2001 with aflexible or swivel suction port 2002. As shown, the port 2002 has anaxis of symmetry that is generally parallel to an axis of symmetry ofthe handle or bone receptacle 2003. The flexibility of the port 2002allows suction be applied even as the port is bent or twisted away fromits relaxed orientation.

FIGS. 21A-C schematically show a bone harvesting device with varioustypes of suction ports. Suction port 2101 is generally perpendicular toan axis of symmetry of the bone receptacle 2102 and located at the endof the bone receptacle. Suction port 2103 is neither parallel to norperpendicular to the axis of symmetry of the bone receptacle. Suctionport 2104 is generally perpendicular to an axis of symmetry of the bonereceptacle, and is located on the side-wall of the receptacle ratherthan at the end. This port also can be oriented with various angles fromthe shown location.

FIGS. 22A and B schematically show a bone harvesting device withmultiple suction ports. FIG. 22A shows a bone harvesting device with twosuction ports 2201, 2202 each connected to a different suction source.FIG. 22B shows a bone harvesting device with two suction ports 2203,2204 each connected to the same suction source. Multiple ports could beincluded as a means to prevent clogging and maintain suction in thebone-harvesting device.

FIG. 23 schematically shows a bone harvesting device with a blood orbiological material reservoir 2301 in the suction line. Since, asexplained above, the bone receptacle can include a filter that preventspassage of bone particles larger than a certain size, but allows passageof blood and smaller particles, it can be useful to station a bloodreservoir in the fluid path of the suction line. The reservoir can beconfigured to allow blood and small particles to settle out of the fluidpath, thus maintaining suction.

FIG. 24 schematically shows a bone harvesting device with depth markings2401 along the cannula. Because the distal tip of the device can behidden inside the bone when in use, external depth markings can help theuser estimate how far inside the bone the distal tip has advanced.

FIG. 25 schematically shows a bone receptacle and screw-on cap withalignment markers 2501 and 2502 to indicate to a user whether the caphas been fully secured to the bone receptacle. When the markers arealigned as shown, the user can be confident that the cap is propertysecured to the receptacle.

FIG. 26 shows a bone harvesting device 2601 with interchangeable distalportions. Distal portion 2602 is similar to the distal portion shown inFIG. 2. Distal portion 2603 curves through a shorter angular arc. Distalportion 2604 is tapered, and curves through a still smaller arc. Distalportion 2605 is essentially straight and curves though no arc at all.Interchangeability allows the user to choose the best tip for any givenapplication. 2604 will not be capable of cutting bone outside of thesite of the cannula whereas 2603 is capable of cutting cancellous boneoutside of the site of the cannula. This is a key feature of thebone-harvesting device enabling it to reach in areas where currentbone-harvesting devices cannot.

FIG. 27 schematically shows a bone harvesting device 2701 with a cannulahaving various different cross-sectional geometries. The cross-sectionas shown could be, for example, circular 2702, elliptical 2704, orirregular 2706, or any other useful two dimensional shape. The cannulamight have ribs on the interior as shown in 2703 and 2705. The variousprofiles could allow for irrigation to flow through the raised regionsand/or other means of positive pressure to aid in clearing thecannulated portion. The profiles may also be apparent from variousmanufacturing processes and by enabling such geometries it can aid inthe manufacturing processes.

FIG. 28 schematically shows a bone harvesting device 2801 with a cannulahaving a wall thickness that varies along its length. Depending onmanufacturing process, variable thickness may aid in ease ofmanufacturing. In addition, the grooves could have irrigation and/orpositive pressure to aid in streamlined suction.

FIG. 29 schematically shows a cap for a bone receptacle with varioussealing points. In one embodiment, a seal 2901 is positioned in thelower surface of the cap 2902, facing the upper surface of a separatefilter assembly 2903. In another embodiment, the seal 2904 is positionedbetween the lower surface of a cap 2905, which includes an integralfilter assembly, and the upper surface of the receptacle 2906. In thatcase the seal is inside the screw threads that affix the cap to thereceptacle. In another embodiment, the seal 2907 is outside the screwthreads that affix the cap to the receptacle.

FIG. 30 schematically shows a bone harvesting device in which thecannula 3001 portion may be curved. A curved cannula may improve thereach of the device and may offer a cutting reach greater than if it isonly straight.

FIG. 31 schematically shows a bone harvesting devices including twocannulas. A device with two cannulas can either include cannulas withcutting portions in parallel 3101, or cutting portions in facingopposite directions or angled in different directions either radially,laterally or longitudinally. 3102.

FIGS. 32A-C schematically show an actuated distal tip. This embodimentprovides an automated cutting action where the user advanced the distaltip into a boney region and cancellous bone and 3201 is scraped into thedistal tip 3202, the cutting surface 3203 or a portion thereof can beactuated so as to close against the opposite side of the distal tip.This will actively cut any bone occupying the opening of the distal tip.The actuated cutting surface can be a spinning blade. The actuation canbe magnetic, electromechanical, purely mechanical (i.e. as by wire), orby any other useful mode. The effect is to bite off bone fragmentsrather than simply to scrape or cut manually with the distal tip.

FIGS. 33A-C schematically show different sharpened distal tips. Tip 3301is sharpened on the inside of the cannula. Tip 3302 is sharpened on theoutside of the cannula. Tip 3303 is sharpened on both the inside and theoutside of the cannula. The tip can also be sharpened in one or moreportions and not in one or more other portions, for example to create aserrated edge or other configuration.

The distal cutting tip can be coupled with irrigation.

All versions of the device described above can be part of a kit that,for example, could include combinations of the following: a flexibleplunger, a stiff plunger, elongated accessory to remove material frombone receptacle, a hole saw, trephine device, drill tap, guidewire,reamer/drill bit, cannulated reamer/drill bit, or reamer/drill bitsleeve for penetrating the compact bone, interchangeable cutting tips,and/or separate biological material catching unit such as a bloodreservoir.

Any of the devices and methods disclosed herein can also includetechnology to allow the user to sense how the distal tip is interactingwith the bone, even when the tip cannot be directly visualized. Forexample the tip could be visualized by use of an infrared or visiblelight camera, possibly an endoscopic camera, by ultrasoundvisualization, by piezoelectric sensors, or pressure or force sensors.

A bone-harvesting device can include a cannula and a bone receptacle.The cannula can include a proximal end, a proximal portion adjacent tothe proximal end that defines an axis, a curved distal portion thatbends through an angle of at least 90 degrees and no more than 180degrees relative to the axis, and a distal end, adjacent to the distalportion, at least a part of the distal end being sharpened to form acutting edge. The bone receptacle can include a suction port and anentry port. The entry port can be attached to the proximal end of thecannula such that, when suction is applied to the suction port, thesuction draws from the distal end of the cannula, through the cannula,and into the bone receptacle. In such bone-harvesting devices, thecannula can further include an occluding member that partially, but notfully, occludes the distal end. At least a portion of the proximalportion can be curved and not lie along the axis. The cross-sectionalgeometry of the proximal portion can vary along the length of theproximal portion. The cross-sectional geometry of the proximal portioncan be constant along the length of the proximal portion. The suctionport can be constructed of a flexible material so that suction may becontinuously applied to the suction port while port is bent intodifferent orientations relative to the rest of the device. An axis ofsymmetry in the suction port can be either parallel or non-parallel toan axis of symmetry in the bone receptacle. The receptacle can include aplurality of suction ports. The receptacle can define a proximal openingand can include a cap removably attached to the bone receptacle therebysealing the opening. The cap can be removably attached with any one of(a) mating screw threads, (b) an interference fit, (c) a latch, or (d) aclip. The exterior of the bone receptacle is configured to be used as ahandle by a human operator. The suction port can be in fluidcommunication with a reservoir configured to allow passage of gases butto trap liquids and solids.

A bone-harvesting device can include a cannula and a bone receptacle.The cannula can includes a proximal end, a straight proximal portion, acurved distal portion, and a distal end, adjacent to the distal portion,at least a part of the distal end being sharpened to form a cuttingedge. The bone receptacle can include a suction port, an entry port, anda filter that (a) fully covers the suction port, and (b) includes atleast two sieves positioned so as to have different orientationsrelative tt the suction port. In such devices each sieve can begenerally planar with no two sieves being parallel. The entry port canbe attached to the proximal end of the hollow cannula such that, whensuction is applied to the suction port, the suction draws from thedistal end of the cannula, through the cannula, and into the bonereceptacle.

A method of harvesting cancellous bone can include selecting a bone in apatient from which cancellous bone will be harvested, the bone includingcancellous bone and compact bone, exposing the cancellous bone bycreating a pilot hole through the compact bone, advancing a distal endof a bone harvesting device into the pilot hole along an axis of thebone harvesting device, the distal end including a cutting edge, andexcavating cancellous bone into the bone harvesting device by applyingthe cutting edge to the cancellous bone in a direction not parallel tothe axis of the bone harvesting device. The method can includecollecting the excavated cancellous bone by drawing the excavated bonethrough a channel defined by the bone harvesting device without removingthe distal end of the bone harvesting device through the pilot hole. Insuch methods, excavating cancellous bone can include excavatingcancellous bone that is not visible along any line of sight through thepilot hole.

We claim:
 1. A bone-harvesting device, comprising; a cannula having alongitudinal axis and an outer face, the cannula including a proximalregion, a distal end region and a distal-most end at a distal extremityof the distal end region; and a bone receptacle in communication withthe proximal end region of the cannula; wherein the cannula furtherincludes (i) a cutting surface positioned at the distal-most end, (ii) apassage that opens at the distal-most end of the cannula, the passageconfigured and dimensioned to permit harvested bone to pass through thecannula from a position adjacent the cutting surface into the bonereceptacle, and (iii) an occluding geometry that partially occludes thedistal-most end of the cannula adjacent the cutting surface, wherein thecutting surface is positioned at least in part radially outward of theouter face of the cannula, and wherein harvested bone moves from aposition adjacent the cutting surface through the passage cannula andinto the bone receptacle.
 2. The bone-harvesting device of claim 1,further comprising at least one additional cannula positionedlongitudinally with respect to the first cannula.
 3. The bone-harvestingdevice of claim 1, wherein the cannula defines a cross-sectional areaavailable for movement of the harvested bone into or through thepassage, and wherein the occluding geometry is a reduced diameter regionat the distal-most end, the reduced diameter region functioning toreduce the cross sectional area available for movement of harvested boneinto or through the passage.
 4. The bone-harvesting device of claim 1,wherein at least a portion of the cannula is non-aligned with thelongitudinal axis of the cannula.
 5. The bone-harvesting device of claim4, wherein at least a portion of the cannula is curved relative to thelongitudinal axis, and wherein the cutting surface is positioned at adistal-most end of the curved portion of the cannula.
 6. Thebone-harvesting device of claim 4, wherein the curved portion of thecannula curves through an angle greater than 90 degrees and no more than180 degrees relative to the longitudinal axis of the cannula.
 7. Thebone-harvesting device of claim 1, wherein the cutting surface is formedby sharpening of the cannula in a region at or adjacent the distal-mostend.
 8. The bone-harvesting device of claim 1, wherein the cannuladefines a varied cross-sectional geometry along its length.
 9. Thebone-harvesting device of claim 8, wherein the cannula defines aproximal portion adjacent the bone receptacle, and wherein thecross-sectional geometry of the proximal portion is constant.
 10. Thebone-harvesting device of claim 1, further comprising a suction port incommunication with the bone receptacle.
 11. The bone-harvesting deviceof claim 10, wherein the suction port allows suction to be applied tothe suction port at different suction port orientations based on atleast one of flexible material construction and rotatable mounting ofthe suction port.
 12. The bone-harvesting device of claim 10, whereinthe suction port is in fluid communication with a reservoir configuredto allow passage of gases, but to trap liquids and solids.
 13. Thebone-harvesting device of claim 10, further comprising a filter that (a)fully covers the suction port, and (b) includes at least two sieveportions positioned so as to have different orientations relative to thesuction port.
 14. The bone harvesting device of claim 1, furthercomprising a plurality of ports in communication with the bonereceptacle.
 15. The bone-harvesting device of claim 1, furthercomprising a cap configured and dimension to be removably attached withrespect to an opening defined in the bone receptacle, thereby sealingthe opening.
 16. The bone-harvesting device of claim 15, wherein the capis removably attached with an attachment mechanism selected from thegroup consisting of (a) mating screw threads, (b) an interference fit,(c) a latch, or (d) a clip.
 17. The bone-harvesting device of claim 1,wherein an exterior of the bone receptacle defines a handle region andwherein the handle region includes a feature or indicia that aligns withthe orientation of the cutting surface at the distal-most end.
 18. Thebone-harvesting device of claim 1, wherein the cannula includes aplurality of cutting surfaces positioned in different radial, lateral orlongitudinal orientations.
 19. The bone-harvesting device of claim 17,wherein the handle further includes a flattened side and wherein theflattened side is clear and includes graduations for estimation of thequantity of harvested bone.
 20. The bone-harvesting device of claim 1,wherein the cutting surface is actuable to further open or close thepassage at the distal-most end of the cannula.